New insights into the benefits of exercise for muscle health in patients with idiopathic inflammatory myositis.

[inclusion body myositis]

With recommended treatment , a majority with idiopathic inflammatory myopathy (IIM ) develop muscle impairment and poor health . Beneficial effects of exercise have been reported on muscle performance , aerobic capacity and health in chronic polymyositis and dermatomyositis and to some extent in active disease and inclusion body myositis (IBM ). Importantly , randomized controlled trials (RCTs ) indicate that improved health and decreased clinical disease activity could be mediated through increased aerobic capacity . Recently , reports seeking mechanisms underlying effects of exercise in skeletal muscle indicate increased aerobic capacity (i .e . increased mitochondrial capacity and capillary density , reduced lactate levels ), activation of genes in aerobic phenotype and muscle growth programs , and down regulation in genes related to inflammation . Altogether , exercise contributes to both systemic and within-muscle adaptations demonstrating that exercise is fundamental to improve muscle performance and health in IIM . There is a need for RCTs to study effects of exercise in active disease and IBM .